The wreckage of a train is pictured after an explosion in Lac-Megantic, in this file picture taken July 6, 2013. A fireball leveled the center of the picturesque lakeside town of Lac-Megantic, after the runaway freight train with 72 cars of crude oil derailed, killing about 50 people. The train was owned by Montreal, Maine and Atlantic Railway Corp.

Police raided the Canadian offices of Montreal, Maine & Atlantic Railway on Thursday in their investigation into the train crash earlier this month that destroyed the center of the small town of Lac-Megantic, Quebec, and killed 47 people.

Sgt. Benoit Richard of the provincial police, Surete du Quebec, told reporters that about 15 people had raided the MMA building in Farnham, Quebec, about 40 miles east of Montreal, “to gather evidence to support criminal charges.”

Richard, who gave no further details, denied reports that police had made arrests. Although police say they consider the center of Lac-Megantic to be a crime scene, prosecutors have not yet laid any charges in connection with the July 6 train crash.

A company official speaking on condition of anonymity said that the railway’s corporate headquarters in Hermon, Maine, were not visited by police on Thursday.

Inspectors from the U.S. Federal Rail Administration had been there several times since the July 6 disaster.

Montreal, Maine and Atlantic, a unit of Chicago-based Rail World Inc., operated the train that crashed into Lac-Megantic.

The train, which was hauling 72 tanker cars full of crude oil and was operated by a single engineer, had been parked for the night on a main line uphill from the lakeside town. After the engineer left, it started rolling downhill, derailed in the center of Lac-Megantic and exploded into a wall of fire.

MMA Chairman Ed Burkhardt was not immediately available for comment on Thursday. In the days after the crash, he publicly questioned whether the engineer had set enough brakes to hold the train in place before he left for the night.

Investigators are still searching the center of Lac-Megantic for clues on the cause of crash. They have said the train’s hand brakes are one focus of their probe.